Existing wire control earphones have a conventional 3.5 mm interface, a USB interface, a Lighting interface and other forms of interfaces. All of these earphones can realize volume adjustment by key control. The principle of the volume adjustment is that a voltage of a corresponding connection wire is changed by pressing volume adjustment keys (including a volume increase key and a volume decrease key), so that a processor at one end of an electronic device adjusts the volume output according to the voltage change of the connection wire, that is, the volume adjustment is implemented by the electronic device.
A volume adjustment process in the prior art is illustrated by taking a wire control earphone with the 3.5 mm interface as an example. The wire control earphone comprises an earphone interface, left ear and right ear receivers, a microphone and a key panel, wherein the earphone interface is provided with left and right ear positive wires, a microphone wire and a ground wire, the positive terminal of the left ear receiver being connected to the left ear positive wire, and the negative terminal thereof to the ground wire, the positive terminal of the right ear receiver being connected to the right ear positive wire, and the negative terminal thereof to the ground wire, and the microphone being connected between the microphone wire and the ground wire. For example, if a start pause key, a volume increase key and a volume decrease key are arranged on the key panel, the start pause key is connected between the microphone wire and the ground wire to enable the microphone wire to acquire a low level when the start pause key is pressed. The volume increase key and a corresponding pull-up resistor are connected in series between the microphone wire and the ground wire. The pull-up resistor is configured to enable the microphone wire to acquire a level signal corresponding to a volume increase control instruction when the volume increase key is pressed, the level signal corresponding to the volume increase control instruction being usually set within the range of 80-120 mV. The volume decrease key and a corresponding pull-up resistor are connected in series between the microphone wire and the ground wire. The pull-up resistor is configured to enable the microphone wire to acquire a level signal corresponding to a volume decrease control instruction when the volume decrease key is pressed, the level signal corresponding to the volume decrease control instruction being usually set within the range of 180-220 mV. In this way, when a user presses the volume increase key once, the level signal corresponding to the volume increase control instruction is output by the microphone wire to the electronic device, and then, the electronic device correspondingly increases the volume according to the set correspondence. When the user presses the volume decrease key once, the level signal corresponding to the volume decrease control instruction is output by the microphone wire to a user terminal, and then, the electronic device correspondingly decreases the volume according to the set correspondence.
However, adjusting the volume through an electronic device will increase the load of a processor of the electronic device, such as a mobile phone, which inevitably affects the speed of the electronic device for processing other data, as well as the response speed of other functions of the electronic device. Therefore, it is very necessary to provide a wire control earphone capable of processing a volume adjustment request independently.